Abstract

The thermal conductivity of -axis textured polycrystallineperovskite and random polycrystallinematerial is reported up to . Based on measurements of the thermal diffusivity, density, and specific heat, the thermal conductivity is lower along the -axis than in the plane by almost a factor of 2, and the anisotropy persists up to at least despite a change in the crystal structure at . The exceptionally low (1.0 W/mK), temperature-independent conductivity perpendicular to the perovskite layer structure is attributed to the density difference between the pseudoperovskite and fluorite blocks in the unit cell, forming a natural nanostructured superlattice.

Received 20 May 2008Accepted 01 August 2008Published online 11 September 2008

Acknowledgments:

This work was supported by the National Science Foundation through a Materials World Network program, Grant No. DMR-0710523. The authors are grateful to other participants of the Network, Professors Robin Grimes (Imperial College, London) and Simon Phillpot (University of Florida) for discussions.